Abstract Newly developed and conventional organic/inorganic geochemical and sedimentological techniques, as well as micropaleontological studies (palynomorphs, foraminifera), resulted in the reconstruction of the depositional environment and an estimation of the resource potential of the Upper Cretaceous black shale/phosphorite sequences in southeastern Egypt. The depositional environment is characterized by a broad, shallow shelf which was separated from the continental hinterland by restricted coastal swamps. Depending on structures on the sea floor and depth of the water column, reducing conditions prevailed. The Campanian/Maastrichtian transgression was interrupted by multiple regressive phases which caused intensive reworking of the marine sediments and enrichment of phosphatic layers. Minor terrestrial influx occurred during the formation of oyster bioherms. Open-marine conditions in the upper part of the section (Dakla Formation) indicate prograding marine transgression.