Impact of Climate and Tectonic on the Distribution of the Source Rock in the Atlantic Oceans

Summary The Cretaceous is a key period of the Mesozoic, during which several worldwide source rocks were deposited in the Central, Equatorial and South Atlantic Ocean. Despite its ubiquitous presence, the evolution of paleogeographic and palaeoceanographic conditions during this period implies a variability (1) in the nature of the source rocks and (2) a diachronism of their deposition in the different segments of the Atlantic oceans. In this work, we discuss this diachronism in relation to the control factors such as the climate (e.g. oceanic currents, upwellings) and the tectonic (evolution of thresholds and gateways), and the impact of OAEs on the source rock enrichment. To achieve this, we used an internal global plate reconstruction model to provide a paleogeographic framework at different key periods (from Aptian to the Turonian) over which we plotted (1) geochemical information for source rock enrichment, (2) indicators of ocean water oxygenation from hard data and (3) results of climatic models. Thus, the subsidence of key thresholds triggers the establishment of oceanic currents at different periods, in the different compartments of the Atlantic, is crucial for the record of the Cretaceous source rocks.